Collaborative study will be undertaken at Bicetre and at Northwestern University Medical Center (Chicago), to identify the nature and cellular distribution of nuclear steroid receptors in the isolated cell types of BPH. In Bicetre, technics for specific enzyme markers and for optimal quantitative characterization of nuclear steroid receptors will be developed. These procedures will be applied to prostate cells isolated by superfusion with appropriate tissue disaggregating enzymes (later separated into specific stromal and epithelial cells), following technics developed in Chicago. The cellular studies in Bicetre will be correlated with light and electron microscopy by shipping epon blocks to Chicago for examination. Optimal methods, once developed, will be applied to BPH samples both at Bicetre and Chicago. The combined results obtained in both studies on isolated prostate cells will be correlated with cell morphology in BPH samples.